1. Field of the Invention:
The present invention relates to a method of controlling an operating speed of a loom in an optimum condition.
2. Prior Art:
The applicant proposed an idea which was described in U.S. Ser. No. 324,536 and European Patent Application No. 89 104 577.5 to increase the operating speed of the loom taking into account a weaving condition during operation of the loom to thereby increase the production rate as much as possible.
The method comprises the steps of judging the quality of a fabric with reference to past data during operation of the loom and setting the operating speed of the loom to increase it or to decrease it on the basis of the result of the judgment of the quality of the fabric. During the controlling of the operating speed of the loom, when the fabric having a deteriorated quality is woven or the operator can not cope with or share a plurality of stopped looms during the controlling of the operating speed of the loom, there occurs a case that the operating condition of the loom is not placed in the optimum weaving operation during the collecting of the past data.
Hence, it is an important factor in the case of the controlling the operating speed of the loom to estimate the operating condition of the loom while the loom is kept in the optimum operating condition.
Accordingly, the object of the present invention is to provide a method of controlling the operating speed of the loom comprising the steps of estimating a stop rate of the loom taking into account a predetermined quality of the fabric and an operator's sufficient time for sharing the loom (hereinafter referred to as an operator's sufficient time) on the basis of the present data during the operation of the loom and setting the operating speed of the loom to the optimum operating condition on the basis of the estimated result.
In view of the object of the present invention, the method comprises the steps of: estimating a stop rate of the loom at the final point of time, the estimation being carried out at a certain point of time during a predetermined period while the operating speed of the loom is controlled to be increased so that the production rate is increased; comparing the estimated stop rate with a predetermined limit stop rate so that the operating speed of the loom is increased when the estimated stop rate is less than the predetermined limit stop rate and the operating speed of the loom is decreased when the estimated stop rate exceeds the predetermined limit stop rate. The limit stop rate is previously determined at least from the quality of the fabric or the operator's sufficient time. The quality of the fabric is generally determined on the basis of stop rate of the loom per length of the fabric (hereinafter referred to as the downtime rate of the loom). That is, as the downtime rate of the loom is increase, the stepped portion is increased in the fabric to thereby deteriorate the quality of the fabric. Accordingly, it is judged that the less the downtime rate of the loom, the better the quality of the fabric. The operator's sufficient time is determined by an operating rate of the loom. That is, the downtime of the loom comprises a waiting time, namely, the arrival time of the operator to the loom and a time needed by the operator for sharing the repair of the loom after the arrival of the operator. If the operator's time is sufficient, the waiting time is increased and the downtime of the loom is increased, whereby the operating rate of the loom is reduced. Accordingly, it is judged that the operator's sufficient time is increased as the operating rate is increased.
The method of controlling the operating speed of the loom comprises the steps of: controlling the stop rate on the basis of the estimated stop rate during the change of operating speed of the loom so that the fabric is prevented from being woven inferiorly during the step of controlling the operating speed of the loom or the operating speed of the loom is prevented from being increased at the state where there is insufficient operator's time.
The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.